Blue pages - No.3

Drainage pattern in Auroville and its adjoining North and Northwestern areas

Auroville is located at a higher altitude than other areas is the Auroville bioregion. The Matrimandir is at a height of 52 meters above the sea. The city area is located averagely at an altitude of 45 - 52 meters. The eastern side (near the sea) of the bioregion is at a minimum altitude. In the west and north western side the height falls to minimum of 2 - 3mtrs. Anpakkam - the Estuary of the flow is at a height of 2.4 meters.

In Auroville, the rainwater flows in all direction, but maximum flow is towards the North -Northwest, East - Southeast and East - Northeast. The area between Samasti and Fertile windmill are 0% runoff areas.

Watershed

The slope and channels of a particular area define the term "Watershed".
The North and Northwestern areas of the bioregion are the "Anpakkam watershed". It is one of the sub watersheds of the Kaluvelly watershed. Harvest has initiated a sub-watershed study last year and a French student - Ms. Mallika PAULIK had given a preliminary report on drainage pattern, nature of channels, slope etc.

Drainage map of the Anpakkam sub watershed

Some abstracts from our study are given hereunder

1. Total area of the watershed = 90 km²
2. Total Number of tanks = 22 (small to big)
3. The three major channels, which collect water for the Anpakkam estuary are

a) Alankuppam - Rayapudhupakkam - Kodur - Anpakkam
b) Irumbai- Thuruvai - Kodur - Anpakkam
c) Vanur - Katrampakkam - Anpakkam

4. Total length of the above channel = 58 kilo meters
5. The slope of the channels = 0.27 %
6. The siltation of the channels = 56 % (lightly to heavily)
7. The Vegetative cover of the channels = 40 %
(for more info contact us @Harvest)

An Automatic Weather Station - A Central Weather Data point for the Scientists, Farmers, Students and Others.

Introduction

Weather information plays a vital role in the field of Agriculture and other related activities. Farmers, scientific persons, government agencies etc obviously depend on weather information to plan their activities. Hence, the data required should be precise and accurate at the micro level for effective performance. Such data assists to calculate the past trend and future forecast. It also helps the farmers to decide on cropping, watering and harvesting periods.

The precise information thus collected helps in controlling the exploitation of the Natural resources as well as in imparting it to alternative technologies.

Automatic Weather Station

Auroville Water Service-Harvest has installed an Automatic Weather Station in Vanur so as to find the micro level weather changes. This station will benefit the villages located within 20 kms radius. The parameters mentioned below will be stored and distributed to the farmers, Government agencies, scientific persons and to others who require the same.

1. Rainfall
2. Wind speed
3. Wind direction
4. Relative humidity
5. Solar radiation
6. Air Temperature

Proposed Location and importance

The above-mentioned Automatic Weather Station is to be installed in the State Seeds Farm, Vanur. It has been felt that this place is viable for easy access and has a possibility of using the existing infrastructure for keeping the equipments safely. It is also believed that the seed farm would be a permanent place for maintaining the continuity of data storage system.

Method of operation

A 12-meter tower will be installed and the Automatic Weather Station will be fitted on top of the tower. The signals will be carried through high core cables to the data logger placed in the Storeroom. The data logger will store the data obtained every 30 minutes. Meanwhile, we can also program it to record the data per 1 minute or as required.

The data logger has a memory to store the data of minimum 15 days. The values will be downloaded through memory module and processed with the help of a computer.

It is proposed that the following data would be arrived from the above said action

Benefits

1. Precise weather data will be provided to farmers living around the villages within a radius of about 20 kms.
2. Government agencies, Education institutions, Non-Governmental organizations and other scientific institution can also benefit from the data.
3. The data will be stored in the archives and made available to the people who are interested in knowing the trend and forecasting analyses.
4. It will also help us to do the water balance study and water level comparison.
5. With the help of this data, reports can be published in the Media for creating awareness among people about the importance of sustaining the natural resources, especially water.

Note: To support this a network of 14 rain gauges has been established ( see the previous blue pages)

For further information contact: harvest@auroville.org.in